CONTENTS

1. GENERAL
1.1 - Where can I find the FAQ?
1.2 - My question is not answered by the FAQ, how can I make a suggestion?
1.3 - Who maintains the FAQ?
1.4 - Who owns and runs the OpenH323 mailing list and OpenH323 web site, and how do I contact them if I am having problems?
1.5 - The FAQ describes something that sounds like my problem, and it refers to a document that I don't really understand. I don't have time for all of this - can I just email someone or contact them via IM and get them to explain it all to me?
1.6 - I'm using pwlib 1.15.0 and openh323 1.5.2 from the openh323.org site, and I have a problem. Will anyone help me?
1.7 - Not used
1.8 - What is OPAL?
1.9 - What are the development plans for OpenH323 and OPAL?
1.10 - What were the H.323 security vulnerabilities reported by the NISCC, and how do they affect OpenH323?
1.11 - Not used
1.12 - What is the license used for PWLib, OpenH323 and OPAL, and why wasn't the GPL used?
1.13 - What restrictions are placed on the software can I combine with PWLib, OpenH323 and OPAL?
1.14 - What license restrictions are placed on changes I make to PWLib, OpenH323 and OPAL?
1.15 - Where did PWLib, OpenH323 and OPAL come from, and who is responsible for it now?

2. MAILING LIST
2.1 - How do I subscribe to the mailing list?
2.2 - How do I unsubscribe from the mailing list?
2.3 - How do I make a posting to the mailing list?
2.4 - What is the mailing list used for?
2.5 - What is the mailing list *not* used for?
2.6 - There is too much traffic on the mailing list. Is there a digest?
2.7 - Is there an searchable archive of the list available?
2.8 - Are there any rules?
2.9 - Who enforces the rules?
2.10 - How can I ensure someone will answer my question? 
2.11 - But I really need an URGENT answer to my question?
2.12 - Who answers questions on the list?
2.13 - I want to help by answering questions? How do I do this?
2.14 - Not used
2.15 - Why aren't there separate lists for users and developers like other projects?
2.16 - Can I ask questions about how to use/debug/understand another H.323 stack? 

3. DOWNLOADING CODE
3.1 - Where can I download source code from?
3.2 - Where can I download binaries from?
3.3 - Where can I get the very latest source code from?
3.4 - How do I access the CVS repository?
3.5 - Where can I get ZIP versions of the source archives?
3.6 - How do I know what version to download?
3.7 - Where can I download a particular version of the code?
3.8 - Why isn't the latest code and information on openh323.org, and why don't you do something about it?
3.9 - What are Janus, Pandora, Mimas, Atlas and Phobos?
3.10 - Where can I download the old PWLib GUI code
3.11 - Why is the configure.in file is missing when I extract source code from the CVS?

4. COMPILING THE CODE
4.1 - The code does not compile - what is the problem?
4.2 - Microsoft Visual Studio will not load the DSP and DSW files provided with OpenH323
4.3 - I know the OpenLDAP/OpenSSL/Foobah library on my system is broken, but OpenH323 uses it anyway. How do I prevent this?
4.4 - How do I cross compile OpenH323 for another platform?
4.5 - Are there detailed instructions for building OpenH323/PWLib on Windows?
4.6 - Can I compile OpenH323/PWLib using VS.NET 2003, VS.net 2005 and Visual C++ 2005 Express Edition?
4.7 - How do I fix the Windows build error "Cannot open include file: 'ptbuildopts.h': No such file or directory"?
4.8 - How do I fix the Windows build  error "Configuring Build Options \ This program cannot run in DOS mode \ Error executing c:\windows\system32\cmd.exe" ?
4.9 - How do I fix the errors in vfakeio.cxx starting at line 411 like "newline in constant", "too many characters in constant", "syntax error: string"?
4.10 - How do I report a bug in the code?  
4.11 - How do I fix errors about a missing function called PIsDescendant or IsDescendant ?
4.12 - How do I fix errors about missing include files like "gsmcodec.h" or "lpc10codec.h" ?
4.13 - How do I fix errors like "Cannot open source file: getdate_tab.c': No such file or directory"?
4.14 - How do I compile OpenH323 on Solaris?
4.15 - How do I make the code smaller?
4.16 - How do I submit patches to the code?
4.17 - How do I fix the following error on when compiling using MSVC 6 "WARNING: the following file requires upgrading: \ C:\Program Files\Microsoft Visual Studio\VC98\INCLUDE\XTREE \ Please run 'msvc6chk upgrade' to upgrade this file"?
4.18 - How do I stop my program from immediately crashing with a dialog saying"The application failed to initialise properly. Click on OK to terminate the application" when I use the DLL versions of PWLib and OpenH323, even though the statically linked versions work OK?
4.19 - How do I fix the following error on Windows when building PTLIB.DLL/OPENH323.DLL "dllmain.obj : fatal error LNK1202: "d:\pwlib.msvc\lib\ptlib.pdb" is missing debugging information for referencing module" ?
4.20 - How do I fix the following error when compiling OpenH323 "This program cannot be run in DOS mode. \ Error executing c:\windows\system32\cmd.exe. \ asnparser.exe - 1 error(s), 0 warning(s)" ?
4.21 - I am compiling Pandora or Janus patch 4 - where is the ASNParser?
4.22 - Where is pwrc, openphone and all of GUI classes?
4.23 - How do I fix warnings about PVXMLSession and OpalVXMLSession not found compiling the opennivr/vxmltest/woomera programs?
4.24 - The configure program for PWLib or OpenH323 is finding the wrong version of a library - how do I stop this?
4.25 - I used to be able to compile PWLib without any problems, but now I get warnings like this "Please remove pwlib\include\ptlib\msos from the tool include path and from the pre-processor options for this project" - how do I fix this? 
4.26 - How do I fix errors compiling asn_grammar.y/asn_grammar.cxx?
4.27 - When I compile pwlib I get warnings like "../common/getdate.y: conflicts: 8 shift/reduce, 18 reduce/reduce" - is this normal?
4.28 - When I compile pwlib I get a warning like "In static member function `static std::ostream& PTrace::End(std::ostream&)': warning: unused variable 'rb' - is this normal?
4.29 - How do I fix link errors about missing functions when compiling DLLs on Windows?
4.30 - How do I link applications statically in Windows?
4.31 - How do I link applications statically on Unix?
4.32 - How do I stop configure from finding the wrong header files on Windows?
4.33 - How do fix errors about missing MSVC80.DLL or MSVCR80.DLL files when debugging using Visual C++ 2005 Express Edition? 
4.34 - How do I fix gcc errors about "PAtomicInteger" when compiling OpenH323 or OPAL?
4.35 - I cannot find the Console Components library files (ptclib.lib and ptclibd.lib) in recent builds of PWLib. Where are they?

5. CODECS
5.1 - Why is there no G.723.1/G.729 codec in OPAL or OpenH323?
5.2 - Can I use the ITU reference code for G.723.1 and G.729?
5.3 - Where can I get licensed G.723.1 and G.729 codec implementations?
5.4 - Can I use the Microsoft G.723.1 codec in  my Windows program?
5.5 - How do I use the H.263 video codec with NetMeeting?
5.6 - How do I add my own audio or video codec to OPAL or OpenH323?
5.7 - What audio codecs are supported by OpenH323?
5.8 - What video codecs are supported by OpenH323?
5.9 - Where can I get more information on plugin codecs?
5.10 - Why does a call using a compressed audio codec use much more bandwidth than expected?
5.11 - What is the effect of changing the number of frames per packet for an audio codec?
5.12 - Why am I getting bad audio quality even though I am using G.711?
5.13 - Why am I getting bad audio when using the G.729 codec?
5.14 - How do I get the same codec in each direction when making a call?
5.15 - Why are there so many Speex capabilities?
5.16 - Does OpenH323 support wide-band codecs?
5.17 - Can I use the H.263 video codec in my program?

6. DOCUMENTATION
6.1 - Where can I get a design document for OpenH323?
6.2 - Where can I find the help file for OpenPhone?
6.3 - Where can I find user manuals for the Openh323 programs?
6.4 - Is there a programming tutorial for OpenH323?
6.5 - Is there documentation on audio codec plugins?
6.6 - Where can I get documentation on the API for PWLib and OpenH323?
6.7 - What documentation is available for OpenH323?
6.8 - Where can I find the specification documents for H.323?
6.9 - Is there a document on the configure.exe program used for configuring OpenH323 and PWLib on Windows?

7. USING OPAL and OPENH323
7.1 - When I make a call I get audio in only one direction. What is the problem?
7.2 - I am behind a firewall and cannot receive incoming calls? Why not?
7.3 - I can establish a connection but no audio is transferred. What is wrong? 
7.4 - How do I call NetMeeting with an OpenH323 client?
7.5 - I hear an echo when I speaking on a H.323 call - what is wrong?
7.6 - How can I test whether my client is working? 
7.7 - I'm sure I have found a problem with OpenH323 - how do I report it?
7.8 - Why am I getting bad audio even though I am using the G.711 codec?
7.9 - Why am I getting bad audio when using the G.729 codec
7.10 - When I start OpenGK/OpenMCU2/OpenIVR as a windows service process it won't start due to "error 1053" or similar error. How do I fix this problem?
7.11 - How does OpenH323 support ENUM dialing?
7.12 - I am getting "Blocked" or other incorrect results when using STUN - how do I fix this?
7.13 - What are the different firewall types reported by STUN, and what do they mean? 
7.14 - Why I am seeing messages like "RTP Packet from SSRC=xxxxxxxx ignored, expecting SSRC=yyyyyyyy" with audio only in one direction? 
7.15 - How many simultaneous calls can OPAL/OpenH323 handle?

8. OPAL and OpenH323 applications
8.1 - What other Open Source projects use OPAL and OpenH323?
8.2 - What commercial and closed-source software uses OPAL and OpenH323?
8.3 - What is the status of the OpenMCU program?
8.4 - How do I use OpenH323 with Asterisk?

9. Programming
9.1 - How do I create a program that uses OpenH323 for call control, but uses an external RTP device?
9.2 - How do get a list of the codecs supported by OpenH323?
9.3 - When I enable PMEMORY_CHECK, I see all sorts of memory leaks reported. How do I fix these?

10. OPAL
10.1 - What is OPAL?
10.2 - Where can I download OPAL?
10.3 - How do I compile OPAL?
10.4 - How do I use SimpleOPAL to make a call?
10.5 - Is OpenH323 now obsolete or deprecated now that OPAL is released?
10.6 - Where can I find documentation on OPAL?
10.7 - How do I use OPAL to make a call to a telephone number?

Change Log

1. GENERAL

1.1 - Where can I find the FAQ?

The FAQ is available at http://www.voxgratia.org/docs/faq.html, and is posted automatically every two weeks to the OpenH323 mailing list. It also available in text form at http://www.voxgratia.org/docs/openh323-faq.txt

1.2 - My question is not answered by the FAQ, how can I make a suggestion?

Send any suggestions by email to craigs@postincrement.com

1.3 - Who maintains the FAQ?

This FAQ is maintained by Craig Southeren of Post Increment who can be reached by email at craigs@postincrement.com

1.4 - Who owns and runs the OpenH323 mailing list and OpenH323 web site, and how do I contact them if I am having problems?

The OpenH323 mailing list is hosted by SourceForge and maintained by Quicknet Technologies. Problems regarding the operation of the list should be sent to Dave Erhart <daviderhart@sourforge.net>. See 2.1 and 2.3 for information on subscribing to the list.

Note that the previous mailing list at openh323@openh323.org went offline in March 2007. 

It is well known that the openh323.org web site contains out-of-date information and a very old version of the code. Feel free to email Quicknet regarding this problem but please don't email the mailing list, or me, as there is nothing we can do about it.

1.5 - The FAQ describes something that sounds like my problem, and it refers to a document that I don't really understand. I don't have time for all of this - can I just email someone or contact them via IM and get them to explain it all to me? 

If you feel the urge to contact the core developers, then understand that you are asking them to give up their time and spend it on your problem. If you can't be bothered spending the time, then why should they?

So before doing emailing or contacting via IM, make sure you do the following:

1. Make sure you have read this FAQ, and any associated documentation, thoroughly, 
2. Search the mailing list, or use Google, to find any posts or documents regarding your problem
3. If you don't understand the existing documentation at all, then you probably won't understand the answer. Consider spending more time trying to understand the problem 
4. Ask specific questions, not general ones
5. Accept that the person you contact may be busy, or in another time zone, and cannot answer your question
6. Be polite 

1.6 - I'm using pwlib 1.12.0 and openh323 1.5.2 from the openh323.org site, and I have a problem. Will anyone help me?

It is very unlikely that anyone will assist you with problem in that version of the code, because it has not been updated since mid-2003. There have been several  mapor stable releases of the system in that time, so you should upgrade to the latest stable build and see if your problem persists. If it still happens with more recent code, then ask again.

And yes, it is known that that the openh323.org only provides these old versions of the code. See 1.4 for more information

1.7 - Not used

1.8 - What is OPAL?

See 10.1

1.9 - What are the development plans for OpenH323 and OPAL?

The latest development plans and milestones can be found at http://www.voxgratia.org/docs/milestones.html

1.10 - What were the H.323 security vulnerabilities reported by the NISCC, and how do they affect OpenH323?

The NISSC announced on 13 January 2004 that they had discovered vulnerabilities in several implementations of the H.323 protocol. This announcement was also released by CERT as Advisory CA-2004-01. 

All releases of PWLib after v1.6.0 contain fixes for the vulnerabilities demonstrated by the NISCC test suite. This includes the Janus and Pandora baseline releases and all subsequent stable and development code releases. 

For more information, see http://www.voxgratia.org/docs/niscc_006489-h323.html

1.11 - What is the status of the OpenMCU program?

OpenMCU was originally created in May 2000 by Craig Southeren as a experiment to investigate some ideas about how an audio MCU might work. A description of the original motivations can be found at http://www.southeren.com/blog/archives/000050.html.

Over the next two years the code was modified by Derek Smithies and Roger Hardiman to include video capabilities and to add extra functions such as support for multiple rooms. The final result of this effort was OpenMCU v1.7.1 which supported both video and audio, but was unstable and difficult to understand. Guilhem Tardy has also released some notes on how to add H.263 support to OpenMCU at http://www.salyens.com/ffcodec/

OpenMCU version 2 was started in March 2004 with support from Citron Networks with intent of fixing the known problems with version 1. The code was almost completely rewritten to be more modular, and the stability issues were addressed. This work ended around August 2004 with a version that only supported audio.

A new project was started in March 2006 with the support of Stonevoice to restore video functionality to OpenMCU. This work is proceeding, and will result in a full-featured version of OpenMCU that supports video and audio.  

1.12 - What is the license used for PWLib, OpenH323 and OPAL, and why wasn't the GPL used?

PWLib, OpenH323 and OPAL are available under v1.0 of the Mozilla Public License (MPL). The MPL was chosen specifically because it permits commercial software to be combined with OpenH323 and OPAL in ways that the GPL does not, but still requires changes to the released code to be contributed back to the community. The exact text of the license used for OpenH323 can be viewed in the CVS here.

A more detailed description of the reasons why the MPL was chosen can be found in my keynote speech that was presented at the Free Software/Open Source Telephony Summit held by the German Unix User Group in Geilenkirchen, Germany in January 2005

1.13 - What restrictions are placed on the software can I combine with PWLib, OpenH323 and OPAL?

The MPL places no restrictions on what software you may combine with PWLib, OpenH323 or OPAL. You can use OpenH323 with closed source software or with Open Source software released under other licenses, provided that the other license allows this.

1.14 - What license restrictions are placed on changes I make to PWLib, OpenH323 and OPAL?

Paragraph 3.2 of the MPL license states:

"Any Modification which You create or to which You contribute must be made available in Source Code form under the terms of this License..."

For the purposes of the MPL, "Modification" is defined as:

"...addition to or deletion from the substance or structure of either the Original Code or any previous Modifications. When Covered Code is released as a series of files, a Modification is:

A. Any addition to or deletion from the contents of a file containing Original Code or previous Modifications.

B. Any new file that contains any part of the Original Code or previous Modifications."

In plain language, this means that any changes you make to any existing OpenH323 source file must be released under the same MPL license. This same applies to any new file that contains part of any previously released code.

However, the MPL places no restrictions on any new files you create that contain wholly original code. You can choose to release (or not release) these files under any license you choose.  Please note that files not covered by the MPL will not be included in the official OpenH323 CVS.

1.15 - Where did PWLib, OpenH323 and OPAL come from, and who is responsible for it now?

PWLib was started by in 1992 by Robert Jongbloed and Craig Southeren, and the copyright for the code was transferred to an Australian company called Equivalence Pty Ltd in 1996. Work commenced on OpenH323 in 1998, and PWLib and OpenH323 was released as Open Source software using the MPL license in the same year. The openh323.org domain name was acquired at this time, and the code was made available via a private server at that web address. OPAL coding started in late 1999 and was released under the same license.

In early 2000, Robert and Craig sold Equivalence Pty Ltd and the rights to the openh323.org domain name to a US company called Quicknet Technologies Inc. They were also employed by Quicknet to support OpenH323 and to develop associated software. The OpenH323 CVS and mailing list was moved to a new server managed by Quicknet. 

The OpenH323 CVS was moved to SourceForge in May 2003. Robert and Craig ceased employment with Quicknet in June 2003.

Currently, the CVS remains hosted on SourceForge while the mailing list is hosted by a mail server run by Quicknet who retain the rights to the openh323.org domain name and the ownership of Equivalence Pty Ltd. There have been no new contributions to the codebase by Quicknet or updates to the openh323.org web site since June 2003.

The project continues to grow and mature thanks to the work of a dedicated group of developers. The following people have accepted the responsibility of CVS write access as well as the ability to close patch submissions, and can be considered to be the people responsible for leading OpenH323, OPAL and PWLib:

Craig Southeren, Damien Sandras

The following developers have CVS write access and are active contributors to the project

Derek J Smithies, Simon Horne, Robert Jongbloed, 

The following developers have CVS write access and contribute occasionally:

Shawn Hsiao, Vyacheslav Frolov, Yuri Kiryanov, 
Kilian Krause, Roger Hardiman, Hannes Friederich

Bruce Ferrell administers the mailing list and SourceForge web site on behalf of Quicknet.

There are many more people (far too many to list) who have contributed time and code to the project. Please accept my thanks, and my apologies that you cannot be listed here.

2. USING THE OPENH323 LIST

2.1 - How do I subscribe to the mailing list?

The only way to subscribe is via the form on the following web page

 https://lists.sourceforge.net/lists/listinfo/openh323-devel

2.2 - How do I unsubscribe from the mailing list?

The only way to unsubscribe is via the form at the bottom of the following web page

https://lists.sourceforge.net/lists/listinfo/openh323-devel

2.3 - How do I make a posting to the mailing list?

Send an email to openh323-devel@lists.sourceforge.net.

2.4 - What is the mailing list used for?

This list is used for asking any questions related to the OpenH323 project or related technologies.

2.5 - What is the mailing list *not* used for?

This list is not used for:

• SPAM 
• Questions unrelated to OpenH323
• Selling your company's services or products
• Finding someone to do your homework/final year project/doctorate

2.6 - There is too much traffic on the mailing list. Is there a digest?

Yes. 

When you subscribe to the list, make sure you select "Yes" on the option labelled "Would you like to receive list mail batched in a daily digest?". If you are replying to messages contained in a digest, please make sure you change the subject line to reflect your question rather than retaining the arbitrary digest title. 

2.7 - Is there an searchable archive of the list available?

Yes. http://sourceforge.net/mailarchive/forum.php?forum=openh323-devel

Archives of the old list can be found at http://www.openh323.org/pipermail/openh323/

2.8 - Are there any rules?

No flaming. No trolls. Be nice. Be warned. 

2.9 - Who enforces the rules?

There are several enforcers who ensure that the rules are applied fairly and consistently. If you are emailed by Craig Southeren or David Erhart for being off-topic, for flaming, or if they indicate that an email thread is closed, it is suggested that you listen carefully unless you have kneecaps you no longer care about.  

2.10 - How can I ensure someone will answer my question? 

There is absolutely no guarantee that someone will answer your question. If you want to maximise the chances of an answer, do the following:

• be polite
• provide enough information to allow the problem to be duplicated by someone else
• describe what you have already done to fix the problem
• don't bother saying you need a reply urgently

An excellent essay on how to ask questions be found at  http://www.catb.org/~esr/faqs/smart-questions.html. Another excellent essay on how to report bugs can be found at http://www.chiark.greenend.org.uk/~sgtatham/bugs.html

2.11 - But I really need an URGENT answer to my question?

Then offer money. Lots of money. But don't bother posting your request multiple times unless you don't mind annoying lots of people as well as looking like a complete loser.  

There is one class of posters who appear regularly asking for urgent help, and these are students asking for help in completing their final year project. Writing a VoIP application seems to be a popular topic for final year university students, and I'm sure that most of them actually do the work themselves. The excellent Ekiga (http://www.ekiga.org - formerly GnomeMeeting) application started in exactly this way.

As always, though, there are students who seem to think that they can leave everything to last minute and then just grab some Open Source project and fill in the missing bits. When this does not work, they post plaintive cries on the list asking if someone has created what they need. Strangely, they seem to think this is a perfectly reasonable request so when they don't get an answer, they keep asking. Amazing.... 

What they should do (apart from starting their project earlier so they have plenty of time to finish) is start working on the code themselves, using one of the sample programs as basis. When they encounter a problem, they should ask specific questions that can be answered by someone who has the time to do so. Asking someone else to provide the entire project working exactly to their specifications is just unreasonable - so please don't waste everyone's time by asking.

2.12 - Who answers questions on the list?

Anyone may answer questions, but the most interesting ones will normally be answered by one of the principal developers who include Robert Jongbloed, Derek Smithies, Roger Hardiman, Damien Sandras or Craig Southeren. If you receive a reply from any of these people, then listen carefully because they are very likely correct.

2.13 - I want to help by answering questions? How do I do this?

If you see a question for which you know the answer, or you see a reply that you know to be incorrect, then please join in the discussion. And be gracious if you make a mistake - being wrong is not a crime but being impolite certainly is. 

2.14 - Not used

2.15 - Why aren't there separate lists for users and developers like other projects?

Feel free to subscribe to the lists on SourceForge as you please.

2.16 - Can I ask questions about how to use/debug/understand another H.323 stack? 

The OpenH323 mailing list is intended for questions and issues related to the OpenH323 stack. If you have questions about a commercial H.323 stack, then you should contact the stack vendor for support. Commercial stacks are usually covered by non-disclosure agreements, so it's unlikely that anyone on the list could help you without breaking that agreement. 

If you have questions regarding H.323 that are not related to OpenH323 or any other specific stack, then the Packetizer site (see http://www.packetizer.com has many excellent resources. It also has information on several H.323 mailing lists (see http://www.packetizer.com/voip/h323/lists.html)

3. DOWNLOADING CODE

3.1 - Where can I download source code from?

The official source code archives (tarballs and ZIP files) are available from the downloads page of the OpenH323 SourceForge project, which can be found at http://sourceforge.net/project/showfiles.php?group_id=80674. These same source archives (and occasionally some other releases) can also be found at the Vox Gratia web site at http://www.voxgratia.org/downloads.html. These releases are identical to those available on the SourceForge site as they are updated by the same maintainer from the official CVS repository.

Please do not use the sources from the download page on the offical OpenH323 web site. These files have not been updated since 2003 

3.2 - Where can I download binaries from?

The Ekiga (http://www.ekiga.org - formerly GnomeMeeting) team maintain up to date binary packages of OpenH323 and PWLib for Linux at at http://www.gnomemeeting.org/index.php?rub=5&pos=0

The XMeeting Project team maintains up to date binary packages for MacOS X at http://sourceforge.net/projects/xmeeting/

Other (very out of date) binaries can be found on the OpenH323 site

3.3 - Where can I get the very latest source code from?

The latest source code is always in the CVS (see 3.4 below), but the Ekiga team maintains very recent source code tarballs for Linux at http://snapshots.seconix.com and http://snapshots.voxgratia.org

If you are downloading from the repository, you have a number of versions to chose from:

See 3.7 below on how to find a particular version of the source code in the CVS

3.4 - How do I access the CVS repository?

The CVS is hosted by SourceForge at cvs.sourceforge.net:/cvsroot/openh323. See http://www.voxgratia.org/docs/openh323_cvs.html for more detailed instructions. A web interface to the CVS can be found at http://openh323.cvs.sourceforge.net/openh323/

See 3.3 above for information on development tags available in the CVS, and 3.7 below on how to find a particular version of the source code.

3.5 - Where can I get ZIP versions of the source archives

ZIP files are now created for recent released, but may not be available for some older version. Windows users can use tar.gz source archives without any problems if an archive program that handles end of line characters and binaries is used. We recommend WinZIP. See section 4.2, 4.7 and 4.8 for related problems

3.6 - How do I know what version to download?

Normally, the recommended stable version is the most recent version available from the SourceForge download page. The recommended versions are also shown on the Vox Gratia home page at http://www.voxgratia.org

3.7 - Where can I download a particular version of the code?

If the version you require is not available on any of the download sites (see 3.1 above) then you will have to extract it from the CVS repository (see 3.4 above). 

Every release of OpenH323 or PWLIB is available as a CVS tag. For example, version 1.6.0 or PWLib is assigned the tag v1_6_0. This is useful for doing compares between versions. 

3.8 - Why isn't the latest code and information on openh323.org, and why don't you do something about it?

The owners of the openh323.org domain name (Quicknet Technologies, Inc) maintain the www.openh323.org web site and the openh323.org mailing list. See 1.4 for how to contact Quicknet.

I'm no longer associated with Quicknet, so I cannot make any changes to the openh323.org web site or mailing lists, even though I do have write access to the CVS (as do several other non-Quicknet people). I maintain a website with the latest information on OpenH323 and OPAL, and other projects at http://www.voxgratia.org

3.9 - What are Janus, Pandora, Mimas, Atlas and Phobos?

These names are all code names for various releases of OpenH323 or OPAL. A full explanation of all of the code names can be found on this page http://www.voxgratia.org/docs/milestones.html, but the important information is that the current stable releases are Phobos (for OPAL) and Atlas (for OpenH323). THe current development builds are Deimos (for OPAL) and Titan (for OpenH323)

For those who are interested, the OpenH323 code names come from the moons of Saturn. The OPAL code names come from the two moons of Mars, which appropriately translate to Fear (Phobos) and Panic (Deimos). Future code names for OPAL will come from star names - the first one will be Centauri. 

 3.10 - Where can I download the old PWLib GUI code?

This code is no longer supported and is not available for download as a tar.gz file or ZIP file. It can be extracted from the OpenH323 CVS using the "pwlib_win32" module

3.11 - Why is the configure.in file is missing when I extract source code from the CVS?

The configure.in files in PWLib and OpenH323 were renamed to configure.ac after the Pandora release as this is now the preferred extension for autoconf files. Unfortunately, the limitation of the CVS modules files do not allow for different file sets for different versions of the same module, which means that the configure.in files have been moved to the CVS "attic". 

This means that extracting older releases of the source from the CVS by tag will not get the configure.in file. The file can be retreived using an explicit CVS checkout command to retrieve, as follows:

cvs co -rPandora_release configure.in

We may be able to fix this problem at some time in the future - announcements will be made if this occurs

4. COMPILING THE CODE

4.1 - The code does not compile - what is the problem?

Yes, the code does compile but something on your system is causing a problem. You need to find what that problem is.

Here are some quick tips:

• Make sure that the pwlib directory is renamed to "pwlib" and the openh323 directory is "openh323", as the original tarball may have different names or your CVS client may have used the module name instead
  
• You need Bison and Flex installed as well as a compiler and associated tools. We recommend gcc and Make for Unix platforms, and Microsoft VS.net 2003 for Windows although other environments are supported. Note that the bison and flex package provided as part of the Windows build instructions (see 4.5) must be installed in C:\TOOLS unless you seriously know what you are doing. 
  
• Check the ReadMe.txt files for more information

4.2 - Microsoft Visual Studio will not load the DSP and DSW files provided with OpenH323

You have downloaded the tar.gz source archive, and then used an archive program that does not correctly handle tar.gz files under Windows which has resulted in project files with incorrect end of file characters. MSVC cannot handle project files of this type, although it does handle source files in this mode.

To fix the problem, use a program like WinZIP that will do the correct conversion automatically, or use .ZIP version of the archives. You can also load the DSP and DSW files into a text editor and fix the end of line characters manually.

If you have this problem, you most likely will have the the problems described in 4.7 and 4.8 as well.

4.3 - I know the OpenLDAP/OpenSSL/Foobah library on my system is broken, but OpenH323 uses it anyway. How do I prevent this?

Run "./configure" for PWLib or OpenH323 with the appropriate flag to disable the module you want to avoid. Use "./configure --help" for a list of these flags.

4.4 - How do I cross compile OpenH323 for another platform?

Set the following environment variables before running "./configure":

export CXX=<toolchain directory>/g++
export CC=<toolchain directory>/gcc

It may also be necessary to tweak LDFLAGS and CFLAGS using environment variables as well, or to disable certain features (see 4.3 above)

4.5 - Are there detailed instructions for building OPAL, OpenH323 and PWLib on Windows?

Instructions for compiling OPAL, OpenH323 and PWLib on Windows can be found at http://www.voxgratia.org/docs/opal_windows.html, http://www.voxgratia.org/docs/pwlib_windows.html and http://www.voxgratia.org/docs/openh323_windows.html

4.6 - Can I compile OpenH323/PWLib using VS.NET 2003, VS.net 2005 and Visual C++ 2005 Express Edition?

Version 1.14 of OpenH323 and version 1.7 of PWLib and all later revisions contain full support for VS.NET 2003. See the build instructions (section 4.5 above) for full information in compiling in that environment.

Project files for VS.net 2005 and Visual C++ 2005 Express Edition were added on 26 June 2006 and are available in all later versions of the code. VC 5 Express Edition is available from:

http://msdn.microsoft.com/vstudio/express/visualc/download/

Louis Marascio has created a set of patches to allow compilation of earlier version of PWLib/OpenH323 with VS.net 2003. These can be downloaded from http://www.louismarascio.com/vsnet2003-openh323.zip

4.7 - How do I fix the Windows build error "Cannot open include file: 'ptbuildopts.h': No such file or directory"?

The file ptbuildopts.h is created from ptbuildopts.h.in by the pwlib/configure.exe program. If this step does not occur, then ptbuildopts.h is not created and the build process will fail. You need to determine why this is happening. See section 4.2 above or section 4.25 for a possible explanations

4.8 - How do I fix the Windows build  error "Configuring Build Options \ This program cannot run in DOS mode \ Error executing c:\windows\system32\cmd.exe" ?

This indicates that the file pwlib/configure.exe program cannot be executed, probably because it is missing or corrupted. Download a new version and make sure it is a working Windows executable. See section 4.2 above for a possible explanation

4.9 - How do I fix the errors in vfakeio.cxx starting at line 411 like "newline in constant", "too many characters in constant", "syntax error: string"?

This is a problem in older versions of PWLib, such as version 1.5.3. Download and use a later version of PWLib downloaded from SourceForge (see 3.1). 

4.10 - How do I report a bug in the code?

4.26 - How do I fix errors compiling asn_grammar.y/asn_grammar.cxx?

These errors are probably due some flag differences in the bison pre-processor, but the solution is very simple. Simply upgrade your code to at least the last Janus release version (as of 1 Nov 2004, this was Janus patch 4) because that version (and all subsequent versions) no longer require the ASN parser to be compiled. See 4.21 for more information

4.27 - When I compile pwlib I get warnings like "../common/getdate.y: conflicts: 8 shift/reduce, 18 reduce/reduce" - is this normal?

Yes, this is normal and does not indicate that there is a a problem. It can be safely ignored.

4.28 - When I compile pwlib I get a warning like "In static member function `static std::ostream& PTrace::End(std::ostream&)': warning: unused variable 'rb' - is this normal?

This warning has been left in to remind us of a potential problem that we need to fix some day. For now, it can be safely ignored.

4.29 - How do I fix link errors about missing functions when compiling DLLs on Windows?

The short answer is that this problem is often a side-effect of the method used to maintain compatibility across various versions of the DLL libraries. The simplest way to solve this problem is to delete the files with the extension ".dtf" and then completely rebuild the DLLs. This should solve the problem.

Why does this work? 

The long answer is that PWLib and OpenH323 attempt to preserve the ordinals used for DLL entry points across different versions of the libraries. To do this, the MergeSym program compares the function signatures in the DLLs to the entry points listed in the .dtf files, and makes sure that the final file ends up with compatible ordinals. The default .dtf files are created on a system with all optional features enabled, which means that if they are used on a system with less features, there are unresolved symbols left over. 

4.30 - How do I link OpenH323, PWLib or OPAL applications statically in Windows?

To create a statically linked application in Windows, you simply need to link with the static versions of the libraries rather than the dynamic ones. A guide to the library names under Windows is show below. Note that you must not mix static and dynamic versions of the libraries in the same executable - this will cause very strange and hard to diagnose errors.

4.31 - How do I link OpenH323, PWLib or OPAL applications statically on Unix?

The standard makefiles allow static executables to be created using the following commands:

"make noshared" - creates a statically linked executable with debug information

"make optnoshared" - creates a statically linked executable without debug information 

4.32 - How do I stop configure from finding the wrong header files on Windows?

The configure program on Windows will search all local hard drives looking for header files and libraries that indicate which compile time options can be enabled. Sometimes, configure will find files that it should not, usually because it is searching through the wrong directories. This can occur if packages such as Cygwin or MSys are installed on the host computer.

In addition, the following environment specific environment variables can be used to customise the directories used for various  compile environment environment. This is especially useful when multiple environments are installed on the same machine, (i.e. having both MSVC 6 and VS.net 2003 installed)

Note that technique can also be used to reduce the time taken to perform the configure scan by not scanning large directory trees or even entire drives.

Note that versions of configure prior to version 1.5 (released on 26 June 2006) do not support ignoring entire drives.

You can also specify directories to ignore on the configure command line using the --exclude-dir command line option, or you can specify the names of additional environment variables that contain directories using the --exclude-env option. See the custom build information for the project specific header file to edit the command line to configure.

4.33 - How do fix errors about missing "MSVC80.DLL" or "MSVCR80.DLL" file when debugging OPAL programs using Visual C++ 2005 Express Edition?

5. CODECS

5.1 - Why is there no G.723.1/G.729 codec in OPAL or OpenH323?

These codecs are covered by patents, and are not available as Open Source implementations.

5.2 - Can I use the ITU reference code for G.723.1 and G.729?

Use of these codecs and the reference implementations still requires licenses from the patent holders. See the relevant ITU specifications for more information.

5.3 - Where can I get licensed G.723.1 and G.729 codec implementations?

There are several companies that sell implementations of these codecs for various platforms. Be prepared to pay more than $10k for each codec implementation, plus $10 per copy sold/used.

Some companies that are known to have licensed codec implementations available are:

• VoiceAge (http://www.voiceage.com) - G.729 and G.723.1 for Windows and Linux

• Intel (http://www.intel.com/software/products/ipp/) - A wide range of codecs

5.4 - Can I use the Microsoft ACM G.723.1 codec in  my Windows program?

It is not clear whether this is legal or not, but there is reason to  believe that usage of the MS G.723.1 codec by programs other than those authorised by Microsoft is in violation of the DMCA. We choose not to use this codec for that reason - you make your own choice.

5.5 - How do I use the H.263 video codec with NetMeeting?

6. DOCUMENTATION

6.1 - Where can I get a design document for OpenH323?

What design documents that do exist can be found at http://www.voxgratia.org/docs/openh323_design.html

6.2 - Where can I find the help file for OpenPhone?

There is no help file (yes - we know there is a link for one). If you write one, feel free to post it to the list

6.3 - Where can I find user manuals for the Openh323 programs?

In most cases, there are no manuals. Help on options can be found by running the program with the "--help" option.

6.4 - Is there a programming tutorial on OpenH323?

Vladimir Toncar has written a tutorial that can be viewed at http://toncar.cz/openh323/tut/. It is available in English, Brazlilian Portuguese and Spanish

6.5 - Is there documentation on audio codec plugins?

Yes - see http://www.voxgratia.org/docs/codec_plugins.html

6.6 - Where can I get documentation on the API for PWLib and OpenH323?

The header files for OpenH323 and PWLib contain API documentation in the Doc++ format. The recommended tool for converting the header files into documents (as of 17 May 2004) is Doxygen (see http://www.doxygen.org) which is much faster and more accurate than the original original Doc++ (see http://docpp.sourceforge.net).

To create the documentation for any particular version of PWLib or OpenH323, run the command "make docs" in the "pwlib" or "openh323" directories. A directory called "html" will be created that contains the documentation in HTML format. Doxygen can also be used to create documents in RTF and LaTex format, as well as the compressed HTML format (.CHM) for Windows.

Up to date versions of the the API documentation can be found online at http://www.voxgratia.org/docs/pwlib and http://www.voxgratia.org/docs/openh323. Compressed archives of the documentation for various releases can be found on the Vox Gratia download page at http://www.voxgratia.org/downloads.html

6.7 - What documentation is available for OpenH323?

A list of all documentation available for OpenH323 can be found  at http://www.voxgratia.org/documents.html

A map (i.e. a list sorted by topic) of all documentation available for OpenH323 can be found at http://www.voxgratia.org/docs/document_map.html

6.8 - Where can I find the specification documents for H.323?

Copies of the specifications for H.323, H.225, H.245 and most related protocols can be found at http://www.packetizer.com/iptel/h323/standards.html

6.9 - Is there a document on the configure.exe program used for configuring OpenH323 and PWLib on Windows?

Yes, see http://www.voxgratia.org/docs/windows_configure.html

7. USING OPENH323

7.1 - When I make a call I get audio in only one direction. What is the problem?

You are probably behind a firewall and are trying to make a call to someone on the other side.. See your software documentation for how to solve this problem

7.2 - I am behind a firewall and cannot receive incoming calls? Why not?

Incoming calls require incoming connections on port 1720. Make sure that your firewall is passing incoming connections on that port to your client, and that your machine supports operation behind a firewall.

7.3 - I can establish a connection but no audio is transferred. What is wrong? 

Make sure the two endpoints share a common codec. 

7.4 - How do I call NetMeeting with an OpenH323 client?

NetMeeting can inter-operate with an Open Source OpenH323 client using only a few audio and video codecs. These codecs are G.711 for audio and H.261 or H.263 for video. 

The G.711 audio codec is available as an Open Source implementation and should be available on all OpenH323 endpoints  that have audio enabled. It requires a 64 kbps connection and is only available in NetMeeting if it is configured for LAN bandwidth.

The H.261 video codec is available as an Open Source implementation should be available on all OpenH323 endpoints that have video enabled. The H.263 video codec, which used less bandwidth and provides better quality, may be available if the optional support has been enabled and the required external library is available.

Several people have added new Open Source audio codecs to NetMeeting that use much lower bandwidth:

7.7 - I'm sure I have found a problem with OpenH323 - how do I report it?

See 4.10  

7.8 - Why am I getting bad audio even though I am using the G.711 codec?

7.9 - Why am I getting bad audio when using the G.729 codec?